Toilet Double Flushing

[ridpath]

I'm experiencing a problem with my toilet where the toilet double flushes. It flushes once (you do have to hold it down) then the cistern fills up above the overflow pipe and essentially reflushes very slowly for over a minute before the water level drops to beneath the top of the overflow pipe. I have absolutely no idea what's wrong with it!

I've not been able to identify the toilet brand, however it has a Fluidmaster 400 Series Inlet Float Valve which rises when flushed. I assume the problem is linked to this. It does rise up to the top after first flush to hit the top cap but water keeps rising. I've felt around the valve and it seems solid, I can't see or feel anything obviously wrong with it. Perhaps I need it replaced, but I could with do with some advice to narrow the problem down.

Thanks very much.

 

[AdamMcC5]

Instead of holding it in on the first flush can you not just push it, let it out and let the toilet flush itself? It sounds like its internally overflowing into the pan and filling at the same rate so its taking water into the cistern at the same time as its putting it back into the pan. If its overflowing then it should be a simple matter of adjusting the water level.

 

[kay-jay]

probably the flush valve not the inlet! is it push button?? most of em you can twist em out rather than needing to remove cistern, this will allow you to inspect the valve, there is a round disc at the base which rises when button is pressed to let water out, sometimes it won't reseat properly and can often be remedied by a good clean

 

[ridpath]

Hi, thank you both for your replies.

I've tested the two suggestions below, unfortunately not solved yet, but I'm narrowing down the problem. The push button which is integrated into the lid is linked to a small lever mechanism which lifts a chain which lifts a plug at the bottom of the cistern. I have manually flushed the cistern by lifting the lid, pulling the chain by hand and holding it. However, it continues to fill past the top of the overflow pipe, even when I re-flush it (I pull the chain again after it reaches the overflow pipe), it still continues to fill for some time (probably around three times the amount required before it stops filling with water).

I've had a feel around the inlet valve. When the large cap rises to the top, water continues to fill the tank from the small circular formation inlets at the base of the valve. Pulling the large floating cap (that rises with the water level) up or down along the valve doesn't appear to do anything (it doesn't feel like it's connected to anyway), should this not be closing the inlets at the base when it reaches the top to stop the water into the cistern? When I move the floating cap, up or down, I can still feel a constant flow of water coming from the inlets.

Thanks again.

 

[PlumbBobBob]

sounds like the inlet valve is on it's way out to me or at least the diaphragm needs changing

 

[WaterTight]

iCan you isolate the water to the toilet? (local isolation valve, mains stopcock or other)

If so do so when the cistern is almost full but not quite up to the level of the internal overflow.

Let it settle and give it a minute.

Has it stopped flushing into the pan? If in doubt put a but of toilet paper in the bowl to see if it gathers new water.

If it's stopped the flush valve is probably fine.

Change the inlet. Fluidmasters are great but nothing lasts forever. Recommend change for same.

 

[ridpath]

Hello, thanks for the replies and the suggestion, I've given the stop-cock method a go.

After switching off the water no more water flows into the bowl. However, when I went back into the bathroom after switching off the water, I looked into the cistern and the water is at the same level as the plug-hole! It's now not going as high as the overflow pipe but still keep flushing continiously and doesn't stop.

What is very strange is that the moment I lift the cistern top slightly (water level is still at plug hole level) and place it back down, toilet stops flushing and fills normally (cistern top has flushing button which is connected to lever connected to chain which lifts plug on end, which opens and reseals the plug hole).

This makes no sense to me as there is no reason the plug would not go down fully the first time. When the flush goes the plug lifts and goes back down (well it should!), why does would lifting the cistern lid (which is essentially doing the same motion, lifting the chain/plug, afterwards make a difference?

Thanks again.

 

[ridpath]

Hi, thanks for all the helpful advice above.

I managed to fix the issue by fitting a new replacement seal just under the top cap of the inlet valve. The old replacement seal was quite worn, though it didn't seem to have a hole in, I assume it's a pressure issue. The seal is much thicker. I followed this video:

How to fix a toilet: replacing the Fluidmaster 400 fill valve seal (HD) - YouTube
Thanks again.

 

[fuzzy]

well done